As shown in FIG. 1, a virtual cluster includes a controller for controlling information transmission and internal nodes and edge forwarding nodes for forwarding information. The edge forwarding nodes are connected to each other by a vFabric logic. The edge forwarding nodes are connected to a border gateway protocol (BGP) router reflector (RR) node of the controller by a virtual generic routing encapsulation (vGRE). A device outside of the virtual cluster performs information transmission through the virtual cluster in the following process: an edge forwarding node FP1 receives a protocol packet sent by the device outside of the cluster and transmits transparently the protocol packet to the controller, and after receiving the protocol packet transmitted by FP1 the controller generates a responsive protocol packet and sends the responsive protocol packet to another device outside of the cluster via another edge forwarding node FP2 as a peer node of FP1. Specifically, the edge forwarding node FP2 can be reached in an interior gateway protocol (IGP) topology. In order to realize the information transmission described above, the vGRE connection between FP1, FP2 and the BGP RR node is required to be advertised to outside of the virtual cluster, that is, the state of a forwarding adjacency (FA) link is advertised to outside of the virtual cluster.
Currently, a method for advertising the FA link state is as follows: an IGP neighborhood relation is established between edge service nodes FPs and between the edge service nodes FPs and the BGP RR node, and when the neighborhood is up, link information between the edge service nodes FPs and between the edge service nodes FPs and the BGP RR node is advertised outside in a flooding way via IGP protocol packet Link State Advertisement LSA/Link State Protocol LSP.
However, in a case that the number of the edge forwarding nodes in the virtual cluster is large, the IGP neighborhood relation is established between every two forwarding nodes, which results in a great pressure on the controller. And in a case that the number of the BGP RR nodes is large, the IGP neighborhood relation is also established between the edge FPs and each of the BGP RR nodes, which will further increase the pressure on the controller. In addition, it is required to perform information interaction between the nodes when the IGP neighborhood relation is established, which has an influence on the advertising speed for the link state. Therefore, the existing method for advertising the FA link state has disadvantages that the pressure on the controller is great and the advertising speed is low.